'This mission was always about pushing the limits of miniaturized technology and seeing just how far it could take us, ' said Klesh.
It was accompanied by two tiny satellites called CubeSats, or in this case, MarCO, for Mars Cube One. The two probes were launched along with the InSight Mars lander and helped NASA watch its descent to the Red Planet. "Future CubeSats might go even farther", Klesh added.
The briefcase-sized craft rode on the Insight Mars Lander, detaching shortly after leaving orbit.
The twin MarCO CubeSats, nicknamed Wall-E and Eve, fell silent hundreds of millions of miles away from Earth, and the space agency says it's been more than a month since it last heard from them - and doubts it ever will again.
According to a blog post published on Tuesday, Feb. 5, WALL-E and EVE (named after Pixar's Oscar-winning 2008 animated movie) are more than 1 million and nearly 2 million miles past Mars respectively. But their real mission was simply to show off their abilities so far from home and prove that such small missions - the total MarCO program only cost $18.5 million - could succeed in deep space.
The mission team fears that the pair of spacecraft has attitude-control issues that are preventing them from communicating with Earth.
"WALL-E was last heard from on December 29, EVE, on January 4".
Nasa has several theories about why it has lost contact with the pair - none of which involve the interference of aliens. On top of that, the CubeSats' batteries may be long dead and fail to recharge by the time they are bathed in full sunlight once more.
WALL-E and EVE are the first interplanetary mission to use CubeSats, a class of mini-spacecraft.
They will continue to fly away from Earth as February goes on which means receiving data even more hard.
NASA has another chance to communicate with the MarCO spacecraft this summer when the duo starts to get closer to the sun and the potential to gather power for battery charging grows. The team will reattempt to contact the CubeSats at that time, though whether their batteries and other parts will last that long cannot be predicted.
Even if they are never revived, the MarCO mission was a spectacular success, NASA said. That includes their experimental radios, antennas and propulsion systems.
The systems used for the MarCOs are produced by commercial companies and are likely compatible with various other types of CubeSats.
With EVE and WALL-E's success, NASA is set to continue launching a variety of new CubeSats in the coming years.